Edge-Reconstructed, Few-Layered Graphene Nanoribbons: Stability and Electronic Properties

We report a first-principles
study of edge-reconstructed, few-layered
graphene nanoribbons. We find that the nanoribbon stability increases
linearly with increasing width and decreases linearly with increasing
number of layers (from three to six layers). Specifically, we find
that a three-layer 1.3 nm wide ribbon is energetically more stable
than the C60 fullerene, and that a 1.8 nm wide ribbon is
more stable than a (10,0) carbon nanotube. The morphologies of the
reconstructed edges are characterized by the presence of five-, six-,
and sevenfold rings, with sp3 and sp2 bonds
at the reconstructed edges. The electronic structure of the few-layered
nanoribbons with reconstructed edges can be metallic or semiconducting,
with band gaps oscillating between 0 and 0.28 eV as a function of
ribbon width.